Open Source Software Defined Radio Platform for GNSS Recording, Simulation and Tracking

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1 Open Source Software Defined Radio Platform for GNSS Recording, Simulation and Tracking ION GNSS Session E3: Software Receivers September 19, 2013 Alison Brown NAVSYS Corporation Colorado Springs, CO

2 Steps for Building an SDR GNSS Signal Simulator Step 1. Install GNU Radio Companion Open Source software Step 2. Purchase GRC compatible SDR that covers GNSS frequency bands Step 3. Configure GRC to record and playback GNSS signals into GPS UE Step 4. Build simulated GRC files using Signal Architect and playback to GPS UE 2

GNU Radio Overview GNU Radio is a free & open-source software development toolkit (http://gnuradio.

3 GNU Radio Overview GNU Radio is a free & open-source software development toolkit ( Designed to be used with low-cost external RF hardware to create SDRs Widely used in academic & industry labs GNU Radio Companion (GRC) is a graphical tool for developers to easily create signal flow graphs and generate flow-graph source code 3

4 Steps for Building an SDR GNSS Signal Simulator Step 1. Install GNU Radio Companion Open Source software Step 2. Purchase GRC compatible SDR that covers GNSS frequency bands Step 3. Configure GRC to record and playback GNSS signals into GPS UE Step 4. Build simulated GRC files using Signal Architect and playback to GPS UE 4

GNSS Frequency Bands BEIDOU GPS GLONASS GALILEO BEIDOU AND GALILEO BEIDOU, GPS AND GALILEO GPS L2

5 GNSS Frequency Bands BEIDOU GPS GLONASS GALILEO BEIDOU AND GALILEO BEIDOU, GPS AND GALILEO GPS L MHz BEIDOU B1I MHz GPS+GALILEO L MHz GLONASS L MHz 1.16 to 1.61 GHz 5

6 GNU Radio Compatible SDRs Ettus USRP family ($675+) B100+WBX (50 MHz-2.2 GHz, 8 Msps) N210+WBX (50 MHz-2.2 GHz, 25Msps, 2x2 MIMO) Nuand blade RF ($420) X40 (300 MHz-3.8 GHz, 40 Msps, 2x2 MIMO) 6

7 Steps for Building an SDR GNSS Signal Simulator Step 1. Install GNU Radio Companion Open Source software Step 2. Purchase GRC compatible SDR that covers GNSS frequency bands Step 3. Configure GRC to record and playback GNSS signals into GPS UE Step 4. Build simulated GRC files using Signal Architect and playback to GPS UE 7

System Architecture Single band w/ GNU Radio Companion Windows / Linux Computer Scenario Plan Signal Architect Software DSF to BIN GNURadio Companion Ethernet data rate supports up

8 System Architecture Single band w/ GNU Radio Companion Windows / Linux Computer Scenario Plan Signal Architect Software DSF to BIN GNURadio Companion Ethernet data rate supports up to 25 Msps 16 bit I/Q data Ethernet or USB Software Defined Radio Ettus USRP N210 Nuand bladerf Etc. DIGITAL GPS UE Coax Garmin emap Novatel DL4-plus Rockwell Collins DAGR Etc. ANALOG 8

9 Dual-Band System Architecture M&tbnid=nTg62EVPGj35kM:&ved=0CAUQjRw&url=https%3A%2F%2Fwww.ettus.com%2Fproduct%2Fdetail bv ,d.b2i&psig=afqjcnhykj0n4ukewinuuud9idhilspa7g&ust= Dual band with GNU Radio Companion & Ettus MIMO Windows / Linux Computer Scenario Plan Signal Architect Software NAVSYS Multiband Expansion Software Ethernet / USB MIMO Cable Software Defined Radio 1 Ettus USRP N210 Nuand bladerf Etc. SDR 2 (slave) DIGITAL - Limited to two radios - All data on one computer - Clock / PPS shared over MIMO cable - Per-radio data bandwidth is halved Coax GUE Garmin emap Novatel DL4-plus Rockwell Collins DAGR Etc. ANALOG 9

10 Multiband System Architecture udxm&tbnid=ntg62evpgj35km:&ved=0cauqjrw&url=https%3a%2f%2fwww.ettus.com%2fproduct%2fdetail vm=bv ,d.b2i&psig=afqjcnhykj0n4ukewinuuud9idhilspa7g&ust= Multi band with NAVSYS Multiband Expansion Software Windows / Linux Computer Scenario Plan Signal Architect Software NAVSYS Multiband Expansion Software... Shared Clock / PPS Software Defined Radio 1 Ethernet / USB Coax SDR 2 SDR N Ettus USRP N210 Nuand bladerf Etc.... DIGITAL - Unlimited radios by using multiple Computers - Allows multiple computers to share data load - Clock / PPS split externally - Full per-radio bandwidth now available GPS UE Coax Garmin emap Novatel DL4-plus Rockwell Collins DAGR Etc. ANALOG 10

11 GRC Dual-Band (MIMO) Record/Playback Flow Graph 11

12 Multiband Approach Comparison With GNURadio & MIMO Easy setup All GNURadio Companion GUI and functionality Limit of 2 radios with ethernet limiting data to 25 Msps, 16 bit I+Q (100 MBps) All data flow through one computer Windows or Linux With NAVSYS Multiband Expansion Software Must manually split clock and PPS Command line interface Unlimited radios, full per-radio bandwidth with DAC bit compression to reduce ethernet bandwidth usage Unlimited computers to share data load Currently Linux only Windows version in development 12

Sample Dual-Band Implementation Dual radio record and playback simulation setup MIMO Example (<= 25 Msps) Left radio: L1, 4Msps (C/A) Right radio: L2, 20Msps (P) Dual band GRC output is directed over

13 Sample Dual-Band Implementation Dual radio record and playback simulation setup MIMO Example (<= 25 Msps) Left radio: L1, 4Msps (C/A) Right radio: L2, 20Msps (P) Dual band GRC output is directed over Ethernet to each radio NAVSYS Multiband Expansion SW Example Left radio: L1, 25 Msps (C/A+P+M ) Right radio: L2, 25 Msps (P+M ) Single band I/Q output is directed over Ethernet to each radio from multiple host computers 13

14 Record & Playback Example Single band, L1-C/A on Garmin GPS III 14

15 Record & Playback Example Dual band, L1-C/A and L2-P(Y) carrier phase on NovAtel DL4-plus 15

16 Record & Playback Example Dual band, L1-C/A and L1-GLONASS on NovAtel FlexPak G2-V1G 16

17 Steps for Building an SDR GNSS Signal Simulator Step 1. Install GNU Radio Companion Open Source software Step 2. Purchase GRC compatible SDR that covers GNSS frequency bands Step 3. Configure GRC to record and playback GNSS signals into GPS UE Step 4. Build simulated GRC files using Signal Architect and playback to GPS UE 17

18 GNSS Signal Architect Software Trajectory generation from Google Earth (KML) or NMEA file Almanac file used to define SVs User defines mask angle, CN0 and GNSS signals/codes to be generated Generates simulated IQ data files at each GNSS frequency for GRC playback into SDRs 18

trajectory 2) IQ datafile is created using GNSS Signal Architect Software 3) IQ datafile is stored on disk on GNURadio Host Computer 4)

19 GNSS Signal Architect Operation Generates simulated IQ data files for playback through GNU Radio into SDRs IQ datafile is read from disk by GRC software and sent to SDR for playback at RF Signal Archiving Signal Creation 1) User selects the simulation parameters and trajectory 2) IQ datafile is created using GNSS Signal Architect Software 3) IQ datafile is stored on disk on GNURadio Host Computer 4) IQ datafile is read from disk by GRC software and sent to USRP N210 for playback at RF Signal Generation Signal Design RF Signal Generation 19

20 GNSS Signal Architect Simulator Software GUI 20

21 Signal Architect Features Base Version Interfaces with any GNU Radio Capable SDR GPS Scenario Generation (Static and Dynamic) GPS L1 Record / Playback + C/A code simulation Real-time RF Signal Visualization Multi-Core Processing to speed signal generation Upgrades Multiband Expansion Software (included with multi-frequency generation) GLONASS(civil codes) GPS Military P+M (L1 and L2) BeiDou, Galileo and QZSS (in development) 21

Simulated Scenario Example Single band, Dynamic L1-C/A

as NMEA file using vehicle and used to generate

through GNU Radio; Can also programmatically generate

22 Simulated Scenario Example Single band, Dynamic L1-C/A on Novatel DL4-plus Dynamic real world track recorded as NMEA file using vehicle and used to generate repeatable Signal Architect scenario file to play back through GNU Radio; Can also programmatically generate precise NMEA/KML files using any available software package

23 Simulated Scenario Example Dual band, Static L1-P and L2-P on Rockwell Collins DAGR

24 Simulated GRC Jammer Option 24

25 Advantages of Open Source SDRs for GNSS Simulation Inexpensive hardware for signal generation from multiple Gnu Radio SDR vendors Intuitive signal flow generation using open source Gnu Radio Companion interface Flexible upgrade path for multi-frequency/multicode generation Upgrade option with GNSS Toolbox Matlab source code allows customized GNSS signal simulation 25

26 Backup

27 Ettus USRP Product Line Model DB Slots Host Intf Max BW (MS/s) DAC ADC MIMO CPU Codes N200 1TX/1RX GigE bit, 400 MSPS 14-bit, 100 MSPS Yes n/a All supported N210 1TX/1RX GigE bit, 400 MSPS 14-bit, 100 MSPS Yes n/a All supported E100* 1TX/1RX Emb bit, 128 MSPS 12-bit, 64 MSPS No OMAP 3730 All, except P E110* 1TX/1RX Emb bit, 128 MSPS 12-bit, 64 MSPS No OMAP 3730 All, except P USRP1 2TX/2RX USB bit, 128 MSPS 12-bit, 64 MSPS Yes n/a All, except P B100 1TX/1RX USB bit, 128 MSPS 12-bit, 64 MSPS No n/a All, except P - Supported codes are currently: L1-C/A, L1-P, L1-GLONASS, and L2-P - Future release: BeiDou 27

Broadband GPS Data Capture for Signal and Interference Analysis

Broadband GPS Data Capture for Signal and Interference Analysis Broadband Data Capture for Signal and Analysis Alison Brown, Jarrett Redd, and Phillip A. Burns, NAVSYS Corporation BIOGRAPHY Alison Brown is the President and Chief Executive Officer of NAVSYS Corporation,